Pump



Oct. 2, 1945. w HUBER 2,385,990

PUMP

Filed Oct. 13, 1943 2 Sheets-Sheet l lmwntor 7/ZuZl/ze w Wlzuber Oct. 2,1945. w HUBER 2,385,990

PUMP

Filed Oct. -13, 1943 2 Sheets-Sheet 2 Zinncutor film f/ll em ll. u berPatented Oct. 2, 1945 Matthew W. Huber, Watertown, N. Y., assignor toThe New York Air Brake Company, a corporation of New Jersey ApplicationOctober 13, 1943, Serial No. 568,091

6 Claims.

This invention is directed to high pressure, high speed pumps the typeusing single acting plungers working in parallel cylinders arranged in acircular series around a drive shaft. The plungers are actuated by aswash plate.

Pumps 01' this general description are known and an advanced typethereof is described and claimed in a prior application Ser. No.462,563, flied Octobe 19, 1942. The pump of the prior application is asmall unit designed for use in feathering propellers for airplanes andsome of its details are ailected by its small size and its intendedenvironment, the latter controlling particularly the feed and dischargeconnections. In most respects, however, it is capable of use in largerunits and for general purposes.

The present application is directed to features which have been foundnecessary or desirable in pumps of larger capacity and for use insituations where the pump body is not submerged in oil, but requirespiped connections for intake and discharge.

The utility of such features involves ease of manufacture inspection andmaintenance, improved lubrication, better bearings. and similarfeatures, all intimately related to features characteristic of the pump.The thrust bearing used to sustain the swash plate is a special form ofthe bearing described and claimed in a prior application Ser. No.498,479, filed August 13, 1943.

The preferred form or the pump with certain modifications of componentsthereof will now be described by reference to the accompanyingdrawings,inwhich Figure 1 is an axial section of the complete pump takenon a plane through the inlet and discharge connections.

Figures 2, 3, 4 and 5 are views of the swash plate and are respectivelyrear elevation, side elevation, face view and section on line 5-5 ofFigure 2.

Figure 6 is a development of the periphery of the swash plate and creepplates, and indicating the circular spacing of the plungers.

Figures '1 and 8 are respectively side and race elevations of the fixedelement of the thrust bearing.

Figures 9 and 10 are respectively an axial section and end elevation ofthe cylinder block.

Figure 11 is a view similar to a portion of Figure 1, showing amodification of the swash plate to throw oil toward the thrust bearing.

Figures 12 and 13 are views similar to Figure 4 showing possiblemodifications oi the channels 1% th: swash plate, to afford a better allimpellins e co The housing for the pump comprises a body portion i5 andhas a mounting flange it which can be given any desired form, that shownbeing intended for use with a particular engine.

The threaded plugs indicated at H are drain plugs and have nothing to dowith the operation of the pump.

The body I5 has a heavy circumferential flange it beyond which is acylindrical sleeve-like projection i9. This mates with the cap generallyindicated by the numeral 21. The cap has a perlpheral flange portionwhich encircles the sleeve is and enters into metal to metal engagementwith the face 01 the flange l8.

The body and cap are connected by a series oi socket headed cap screwsindicated at Ill. Since the internal hydraulic pressure is high, aconsiderable number of screws are required. Eight are used.

The pump is shown full size in the drawings filed with the application.

The cap II has a threaded inlet connection 22 which leads to an axialbore 23 communicatin with a hollow shalt hereinafter described. The capalso has a discharge connection II which communicates directly with thedischarge chamber 25, which encircles the passage 23 within the cap, andthus receives oil from all of the discharge valves 01 the pump.

The connections 22 and 24 can be variously arranged, and it is a simplematter to furnish caps or special design suited to particularinstallations.

The cylinder block of the pump is of special form and involves a numberof novel features. This cylinder block is shown in detail in Figures 9and 10.

The block proper comprises an annulus It bounded by two plane surfacesexcept that on the right-hand face, as viewed in Figure 9, there arerabbets 26 and 21 designed to receive annular sealing gaskets 28 and 29.

These gaskets are made of any suitable oil resisting rubber-likecomposition, certain 01' the synthetic rubber substitutes beingsuitable. The gaskets are circular in cross-section but when placedunder compression fill the rectangular grooves as indicated.

The cylinder block 00 has nine cylinder bores 3| which are arranged in auniformly spaced circuiar series parallel with the axis of the block. Toafford inlet ports the following construction is adopted. The peripheryof the cylinder block 30 is cut away to receive the ring I! which ispressed to place. Before the ring I! is mounted, a peripheral slot 33 isout so that it intersects all of the bores 3i and extends inwardslightly beyond the inner margin of each cylinder bore. A series ofinlet ports 34 lead from the space to the left of the block 30 to theslot 33.

Nine bores II are indicated in Figure so that the groove 33 is suppliedwith oil close to each piston and very free flow to the inlet port isafforded. Except for the use of the ring I! pressed to place, therovision of the slot N and the ports 34 would weaken the cylinder blockmaterially.

The construction provides a block which can be easily manufactured,which has ample inlet port area, and which nevertheless has adequatestrength.

Pressed into the central bore of the cylinder block '30 is a bearingbushing 35. This bushing is flush with the left-hand face of the blockII but terminates short of the rabbet 21, and the central portion of thecap 2| is so dimensioned that it extends past the rabbet 21 andvirtually into contact with the end of the bearing bushing. Thus thegasket 29 is positively confined in all directions. The same is true ofthe gasket 28 since the confining portion of the cap enters the rabbet26 and seats on the outer end of the sleeve is. It may be observed thatthe cap is not in metal to metal contact with the cylinder block 30, andit might be assumed that the block could move to the right, compressingthe gaskets 28 and 29.

In operation the cylinder block is under discharge pressure in thechamber 25 and consequently is held to the left against the seat 38formed in the housing ii.

In each of the cylinder bores BI is a plunger 81, essentially similar tothe plunger used in the prior application above identified. Each plungerhas a flanged head in which is mounted a thrust ball 38 having aprojecting boss formed with the flat bearing surface. These balls aresnapped or pressed into spherical sockets which are slightly deeper thanthe radius of the ball so that the balls are captive after being pressedto place. Each plunger is urged outward by a coil compression spring 38,which encircles the plunger and reacts between the cylinder block andthe flanged head of the plunger.

In its outermost position indicated as to the lowermost plunger inFigure l the end of the plunger overtravels the right face of the slot33 in the cylinder block and consequently admits oil to the bore 3| tothe right of that slot. This is the provision for the admission of oilto the pump working spaces.

It will be observed that the flow path for oil is very large as comparedto the port opening.

As indicated with reference to the uppermost plunger in Figure 1 eachplunger has an axial bore leading from its end to branch passages whichlead to encircling lubricating grooves. In this way the plungers arelubricated by the oil being pumped. Since no novelty is here claimed forthis arrangement, the lubricating ports are not numbered on thedrawings, but they are adequately illustrated.

As in the structure of my prior application above identified, thedischarge valves are larger than the bores 3| and there is one valve foreach bore. The valves are cup-shaped members ll guided in bores formedin the cap 2| and axially aligned with bores ii in the cylinder block.

Each valve seats on the right-hand face of the cylinder block and isurged to its seat by a coil compression spring 42. The space within thecup-shaped valve is vented by ports 43, four such ports being used ineach valve. Obviously the discharge from each of the bores ll occurspast the valve directly into the discharge chamber 25.

In the preferred construction the plunger does not strike the dischargevalve, but the minimum practicable clearance is used. It is knownpractice so to dimension plungers in pumps that they positively unseattheir discharge valves. There is nothing in the present invention whichprecludes the use of this arrangement in any instance where it isdesired. The construction is not deemed to have any particularadvantage. It is believed, however, that the best action is secured byproviding practically no clearance between the end of the plunger andthe valve, but since the fluid pumped is substantially inelastic, theuse of small clearance has not the importance that it has where a veryelastic fluid is pumped.

The drive shaft for the pump is indicated at It and is counterbored fromits right-hand end so that the bore communicates with the inlet passage21. The swash plate which actuates the plunger is indicated generally bythe numeral 45 and is keyed at 4' to the solid left-hand portion of theshaft 44. The swash plate has a hub which turns in a radial bearingsleeve bushing 41.

This sleeve bushing is pressed into the fixed thrust bearing element 48which in turn is fixed in a circular seat formed in the housing It toreceive it.

The arrangement of the thrust bearing and the oil ports is a specialfeature of the present invention. Reference should now be made toFigures 2 to B which show details of these parts.

The fixed thrust bearing element 48 which is best shown in Figures '7and 8, has a discontinuous thrust surface 49. That is to say, the thrustsurface is interrupted by a series of grooves 5i whose form is wellillustrated in Figures 7 and 8, the slots being generally radial. Theedges of the bearing surface 49 adjacent the slots are relieved orbevelled as indicated at 52. The small ports 50 which lead from theslots are intended to deliver oil to the shaft seal. Resting on thethrust hearing surface It and centered by a flange on the radial bearingbushing 41 is a creep ring 53.

A second creep ring I4 is engaged by the flat thrust surfaces on theballs 38 on the various pump peripheries, and this creep ring 54 iscentered by the hollow shaft ll.

The swash plate 45 is interposed between the two creep rings II and 54.

While the swash plate could be solid except for radial oil portshereinafter described, it has been found desirable to form it as bestshown in Figures 2 to 6 inclusive. Thus its margin has a zigzagconfiguration so that the left side, which forms the thrust bearingside, has a series of interrupted bearing areas 55 each with a chamferedmargin II. The inclined side of the swash plate ll, which engages thecreep ring Bl also has an interrupted series of bearing areas 61 withchamfered margins II.

As clearly shown in Figure 2 this interrupted area of each bearing areasubtends approximately of arc, and the angular spacing of thedisconnected areas is such that it coincides with the circumferentialspacing of the plungers l'l. See Figure 6.

It is necessary that the oil entering through the connection Iii reachthe space within the housing ll so that it can flow to the passages II.The invention provides for this by delivering the oil through radialports 8!.

As indicated in Figure 2 there are flve ports which deliver oil from thebore of the shaft If to the intervals formed by the fluted constructionof the swash plate 4!. There are also two diagonal ports ll (seeparticularly Figure 5) which deliver oil to the radial bearing bushingI! so that the radial bearing and the bearing surface between the swashplate and the creep plate are adequately lubricated.

It may be remarked in passing that Figure 6 seems to show the peripheryof the creep plate It as sinuous. It is probably unnecessary to say thatthis follows from the fact that Figure 6 is a development. so that theintersection of the cylinder with an oblique plane surface appears as asine curve.

To prevent leakage of oil from the housing I! it is necessary to providean oil seal around the left end of the shaft ll. Immediately to the leftof the hub of swash plate It the shaft is reduced somewhat in diameterand provided with a groove in which is snapped an elastic sealing ring82 of oil resisting material, such a a synthetic rubber substitute.

This ring sustains a sealing annulus ll whose left surface is a lappedplane surface. This plane surface coacts with a head on a sealing ringN. The sealing ring it is held in the housing II by the flange of anencircling nut I threaded into a recess in the housing it. The ring '2seals the ring it to the shaft and furnishes the necessary elasticsupport to cause the ring II to run in oiltight contact with the fixedring '4.

Further to the left the shaft is reduced in diam. eter as indicated atII, and beyond this point of reduction, is formed with a dental clutcharrangement generally indicated at 61. This dental clutch is of a knowntype in which the two engaging members are loosely fitted to assure aposi tlve driving connection without imposing any lateral flexure on thedriven shaft in the event that it should be slightly misaligned.

Since the oil enters at 22 and flows through the passage 21 and the boreof the shaft II and is thence thrown radially through the passages 89,there is an impelling action which maintains the interior of the housingIt under a positive oil pressure. This is highly desirable because itgives a supercharging effect. It puts the port slot If in the cylinderblock under pressure and thus improves the volumetric efllciency of theplunger pump. It also assures lubrication of the bearing surfaces.Certain expedients may be adopted to enhance these effects.

Figure 11 is identical with a portion of Figure 1 except for the curvedconfiguration indicated at II. This is designed to throw the dischargingofl to the left and thus improve the lubrication oi the thrust bearing.Aside from this detail there is not difference between the structure ofFigure 1 and Figure ll.

The construction shown in Figures 12 and 13 can be combined with theconfiguration of Figure 11 or with that shown in Figure 1. In Figure 12it is assumed that the pump will be driven in one rotary direction only,and in that case the ribs ll of the flutes in the swash plate, which areshown as radial in Figures 2 3 and 4 are curved rearwardly for thepurpose of enhancing their operation as impellers. The swash plate isassumed to turn in the direction of the arrow on Figure 12.

The plunger part of the pump is, however, indifferent to the directionof rotation of the swash plate, and as a rule it is desirable for thepumps to be capable of operation equally well when driven in eitherdirection. In any case where it is desired to enhance the impeilingaction, and still preserve indifference to the direction of rotation.the flutes may be given the double convex configuration indicated at I!in Figure 13. This is believed to give better impelling action than ishad with the plane radial flutes of Figures 2, 3 and 4 but not quite sogood as that had with the arrangement shown in Figure 12.

Because of its markedly greater simplicity in manufacture the form shownin Figures 2 to 5 is expected to be the commercial form, and the amodified forms are likely to be used only in cases where exceptionalperformance is necessary.

What is claimed is:

l. The combination of a pump housing having inlet and dischargeconnections; a rotary drive shaft, mounted in said housing, projectingat one end therefrom. and having a counterbore at its inner end. incommunication with said inlet connection; means forming a plurality ofcylinders arranged in circular series around said shaft within thehousing; plungers reciprocable in said cylinders; valves controllingflow from the cylinders to the discharge connection; means including aswash plate turning with said shaft within the housing and arranged toreciprocate said plungers; means controlling flow from the interior ofsaid housing around said swash plate to said cylinders; and impellingmeans formed as a part of the swash plate and adapted to. draw liquidthrough said inlet and shaft and discharge it into the space around theswash plate within the housing.

2. The combination of a pump housing having inlet and dischargeconnections; a rotary drive shaft, mounted in said housing, projectingat one end therefrom, and having a counterbore at its inner end, incommunication with said inlet connection; means forming a plurality ofcylinders arranged in circular series around said shaft within thehousing; Dlungers reciprocable in said cylinders; valves controllingflow from the cylinders to the discharge connection; a fixed bearingmember mounted in the housing and having an interrupted thrust bearingsurface; a swash plate mounted to rotate with said shaft and fluted toafford an interrupted thrust bearing surface and an interrupted inclinedswash bearing surface: creep plates interposed respectively between saidthrust bearing surfaces and between the swash bearing surface and saidplungers; means urging the plungers toward the swash plate; impellingmeans including portions of said flutes for drawing liquid through theinlet connection and shaft and delivering it into the space within thehousing around the swash plate; and means for admitting liquid from thelast named space to the cylinders.

3. The combination defined in claim 2 in which the flutes havinginclined deflecting surfaces serving to direct liquid dischargingtherefrom toward said fixed bearing member.

4. In a pump, the combination of a rotary swash plate having oppositebearing surfaces, one of which is normal to the axis of rotation toserve as a thrust bearing and the other is inclined relatively to theflrst. each of said surfaces being recessed to form a circumferentialseries of spaced plain bearing areas; creep plates one seated againsteach of said thrust surfaces and rotatable relatively thereto; a fixedbearing member having a thrust bearing surface which is interrupted toafford a circumferential series of spaced plain bearing areas whichengage the first creep plate; a plurality of plungers arranged withtheir axes spaced in a circular series around and substantially parallelwith the axis of rotatlon of the shaft; universally tiltabie thrustheads mounted at the ends of said plungers and engaging the second creepplate: and means serving to maintain engagement between the thrust headsand the second creep plate.

5. In a pump, the combination of a rotary swash plate having oppositebearing surfaces, one of which is normal to the axis of rotation toserve as a thrust bearing and the other is inclined relatively to thefirst, each of said surfaces being recessed to form a circumferentialseries of spaced bearing areas; creep plates one seated against each ofsaid thrust surfaces and rotatable relatively thereto; a fixed bearingmember having a thrust bearing surface which is interrupted to afford acircumferential series of spaced bearing areas which engage the firstcreep plate; a plurality of plungers arranged with their axes spaced ina circular series around and substantiaily parallel with the axis ofrotation of the shaft: universally tiltable thrust heads mounted at theends of said plungers and engaging CERTIFICATE OF Patent No. 2, 585,990.

MATTHE W.

assspoo the second creep plate; means serving to maintain engagementbetween the thrust heads and the second creep plate: a hollow rotatableshaft upon which said swash plate is mounted: and means for passingliquid flowing to the pump through said shaft and thence through the recesses in the swash plate.

6. In a pump, the combination of a rotary swash plate having oppositebearing surfaces, one of which is normal to the axis of rotation toserve as a thrust bearing and the other is inclined relatively to thefirst, each of said surfaces being recessed to form a circumferentialseries of spaced bearing areas: creep plates one seated against each ofsaid thrust surfaces and rotatable relatively thereto; a fixed bearingmember having a thrust bearing surface which is interrupted to afford acircumferential series of spaced bearins areas which engage the firstcreep plate: a plurality of plungers arranged with their axes spaced ina circular series around and substantially parallel with the axis ofrotation of the shaft: universally tiltable thrust heads mounted at theends of said plungers and engaging the second creep plate; means servingto maintain engagement between the thrust heads and the second creepplate; and means for causing liquid flowing to the pump to pass throughthe recesses in the swash plate and in contact with the creep plates.

MATTHEW W. HUBER.

CORRECTION.

October 2, 191

HUBER It is hereby certified that error appears in the printedspecification of the above numbered patent requiring correction asfollows: Page 5, sec and column, line 61, claim 3, for the word "having"read "have"; and that the said Letters Patent should be read with thiscdrrection thereinthat the same may conform to the record of the case inthe Patent Office.

Signed and sealed this 1st day of January, A. D. 192 6.

(Seal) Leslie Frazer First Assistant Commissioner of Patents.

one seated against each of said thrust surfaces and rotatable relativelythereto; a fixed bearing member having a thrust bearing surface which isinterrupted to afford a circumferential series of spaced plain bearingareas which engage the first creep plate; a plurality of plungersarranged with their axes spaced in a circular series around andsubstantially parallel with the axis of rotatlon of the shaft;universally tiltabie thrust heads mounted at the ends of said plungersand engaging the second creep plate: and means serving to maintainengagement between the thrust heads and the second creep plate.

5. In a pump, the combination of a rotary swash plate having oppositebearing surfaces, one of which is normal to the axis of rotation toserve as a thrust bearing and the other is inclined relatively to thefirst, each of said surfaces being recessed to form a circumferentialseries of spaced bearing areas; creep plates one seated against each ofsaid thrust surfaces and rotatable relatively thereto; a fixed bearingmember having a thrust bearing surface which is interrupted to afford acircumferential series of spaced bearing areas which engage the firstcreep plate; a plurality of plungers arranged with their axes spaced ina circular series around and substantiaily parallel with the axis ofrotation of the shaft: universally tiltable thrust heads mounted at theends of said plungers and engaging CERTIFICATE OF Patent No. 2, 585,990.

MATTHE W.

assspoo the second creep plate; means serving to maintain engagementbetween the thrust heads and the second creep plate: a hollow rotatableshaft upon which said swash plate is mounted: and means for passingliquid flowing to the pump through said shaft and thence through the recesses in the swash plate.

6. In a pump, the combination of a rotary swash plate having oppositebearing surfaces, one of which is normal to the axis of rotation toserve as a thrust bearing and the other is inclined relatively to thefirst, each of said surfaces being recessed to form a circumferentialseries of spaced bearing areas: creep plates one seated against each ofsaid thrust surfaces and rotatable relatively thereto; a fixed bearingmember having a thrust bearing surface which is interrupted to afford acircumferential series of spaced bearins areas which engage the firstcreep plate: a plurality of plungers arranged with their axes spaced ina circular series around and substantially parallel with the axis ofrotation of the shaft: universally tiltable thrust heads mounted at theends of said plungers and engaging the second creep plate; means servingto maintain engagement between the thrust heads and the second creepplate; and means for causing liquid flowing to the pump to pass throughthe recesses in the swash plate and in contact with the creep plates.

MATTHEW W. HUBER.

CORRECTION.

October 2, 191

HUBER It is hereby certified that error appears in the printedspecification of the above numbered patent requiring correction asfollows: Page 5, sec and column, line 61, claim 3, for the word "having"read "have"; and that the said Letters Patent should be read with thiscdrrection thereinthat the same may conform to the record of the case inthe Patent Office.

Signed and sealed this 1st day of January, A. D. 192 6.

(Seal) Leslie Frazer First Assistant Commissioner of Patents.

